The present invention relates to a roll-to-roll inkjet coating device and a roll-to-roll inkjet coating method used for manufacturing a flexible material using inkjet coating.
Further, the invention relates to an inkjet coating device and an inkjet coating method for stably performing coating of a material having an ultraviolet curing function (hereinafter also referred to as UV curing function).
An inkjet method denotes a method of ejecting ink droplets of a small amount with high accuracy from an inkjet coating head using bubbles or a piezoelectric element.
In the past, as an example of a printing device, there is disclosed in JP-A-9-239968 a printing device provided with an introducing section for introducing a print medium while performing an anti-wrinkle process and an alignment process in the width direction on the print medium, a conveying section disposed adjacent to the introducing section so as to be opposed to the print medium and for conveying the print medium with a belt, a print section disposed so as to be opposed to the print medium and having a plurality of lines of line heads corresponding to the number of kinds of colors, and a drying section disposed on the downstream of the print section in a direction in which the print medium is conveyed in the print section, and for drying the print medium after printing.
In such a printing device, the anti-wrinkle process, a process of centering with respect to the center along the conveying direction, a texture correction process, and a process of correcting curl on both edges (both selvages of a fabric) are performed on a sheet-like print medium (e.g., a fabric roll or fabric housed in a box) using a plurality of rollers.
Further, regarding a nozzle vacuum suction section, there is disclosed in JP-A-2008-272996 a technology of creating the condition in which ink can be ejected stably by covering a coating head, and setting the inside of the coating head to appropriate negative pressure by a suction section to thereby remove bubbles inside the coating head.
As support to the ink liquid types (an ink liquid of a UV-curing coating material; hereinafter referred to as a UV-curing coating material) there can be cited a technology for preventing the ink liquid from being cured before landing and rapidly curing the ink liquid after landing. In order to realize the technology, there is disclosed in JP-A-2004-314304 a technology provided with coating heads attached to a carriage moving in a main scanning direction, UV light sources, and covers covering the respective UV light sources.
A side surface of the cover extends downward beyond a lower surface of the coating head, and is disposed between the coating head and the UV light source. A lower end of the side surface of the cover is provided with a flange extending toward a course of a droplet.
According to such a configuration, ultraviolet light from the UV light source is shielded by the side surface of the cover, and thus, the ultraviolet light is prevented from reaching the coating head and the course of the ink droplet of the UV-curing coating material ejected from the coating head. Further, the ultraviolet light reflected by a recording medium is shielded by the flange, and the ultraviolet light thus reflected is prevented from reaching the head and the course of the droplet.
A film unrolled and then conveyed in the roll-to-roll process includes both of a region with a semiconductor material deposited on the surface of the film and a region without the semiconductor material. Therefore, both side end regions in the width direction of the film become in a curled state. When holding the film, thus wound off from the roll as described above, for coating with a coating material by sucking using a suction table, if the curl exists in the both side end regions, it becomes difficult for the film to be sucked evenly on the suction table. Therefore, there arises a problem that wrinkles or slacks is caused. As described above, if the wrinkles or the slacks is caused, a nozzle tip surface of an inkjet head or the like for coating has contact with the film, and the nozzle surface might be damaged.
Further, in the coating process of the related art using the UV-curing coating material, there have been cited the following three stages as the states for considering whether or not the curing is allowed. Specifically, there have been sited the stage before ejection in which the material is stored in the coating head, the stage (the stage corresponding to the movement along the “course of a droplet” in JP-A-2008-272996) in the process of ejection in which the material has been ejected from the coating head but not yet arrived at an object substrate, and the stage in which the ejected UV-curing coating material has been arrived at the object substrate. In the former two stages, it is preferable that the UV-curing coating material is not cured, while in the last stage in which the droplet of the UV-curing coating material has arrived at the substrate, it is preferable that the material is cured at once.
However, the situation in which it is desired that the UV-curing coating material is not cured is not limited to the case in which the material is stored in the coating head or the case in which the material is in the process of ejection from the coating head. Although the inside of the coating head is filled with the UV-curing coating material, by continuously repeating the coating process, there arises a problem that bubbles are incorporated into the inside of the coating head gradually as time advances.